Vehicle adaptive cruise control (ACC) is an advanced driver assistance system (ADAS). The ACC system is a development version of a cruise control (CC) system. In the ACC system, controlling parameters for a throttle or a breaking are calculated by measuring a distance from a host vehicle to a target vehicle and a relative speed to the target vehicle and a vehicle control or a distance control is implemented by adaptive adjustment. With the ACC system, a driver may drive the vehicle easier and a collision control may be achieved so as to improve safety, comfort and low cost for the vehicle driving.
Regarding to the safety, according to statistics of World Health Organization, (Broggi A., Zelinsky A., Parent M., Thorpe C. E. Intelligent vehicles, In Spring Handbooks of Robotics, Siciliano B., Khatib O. (Eds.), Springer-Verlag Berlin Heidelberg 2008, pp. 1175-1198.), there are about 1.2 million died and 5000 wound in the traffic accident in the whole world. Among which 90% are caused by drivers' fault, including fatigue, drunk, speeding, and so on. An average response time of normal drivers to emergency is about 1 second, while the response time of vehicle ACC is rather less. Therefore, the ACC is effective to avoid most traffic accidents with ACC.
Regarding to the comfort, traffic jams often occur in urban city, so that drivers should frequently stop and go, which needs lots of pedal switching activities, about 20-30 feet and hands coordination per minute. (Zhimei Gan. Stop&Go Cruise Control Based on Laser Radar. Shanghai Jiaotong University Master Thesis, 2009.) This is a main reason of driving fatigue. ACC can liberate the driver from frequent speeding up and slowing down and reduce the drivers' mental stress. Drivers can really enjoy the driving process.
Regarding to the low cost, recently low energy cost and low carbon emission are advocated. As well known, most waste emission is released during low speed driving, and ACC provides an optimized economic driving mode. On the other hand, a proper distance may be kept between the vehicles provided with the ACC system so as to improve a passage capacity and alleviate traffic jam. It is demonstrated that if a quarter vehicles were equipped with the ACC system in highways, the congestion would be effectively avoided. (Kesting A., Treiber M., Schonhof M., Helbing D. Adaptive cruise control design for active congestion avoidance. Transportation Research Part C, 2008, 16: 668-683.).
However, different drivers have different driving habits. This puts forward a high requirement for the ACC controller design. Otherwise, the driver may prefer to cancel the ACC function. Details are discussed in (Rajaonah B., Anceaux F., Vienne F. Trust and the use of adaptive cruise control: a study of a cut-in situation. Cognitive Technology Work, 2006, 8: 146-155.).
In general, there are some advantages in a conventional ACC system. However, when controlling the speed and the relative distance, the conventional ACC system can't perform adaptive adjustment based on different driving habits under various driving scenarios to improve the driver experience.
Therefore it is needed to provide an improved ACC system to address the advantages mentioned above.